[TVARC] Advice wanted: Wire antennas in attics

[Jim Worthington]

I have some experience with attic antennas. The closest to what you suggest are 40-20-10 meter fan dipoles I’ve installed for in a couple homes near Melbourne, FL. The 40 meter section works on 15 meters giving 4 bands, but requires the internal tuner on 15.

In addition, I have a makeshift 40-10 meter doublet in an attic in Fenney and a couple of switchable, perpendicular 10-6 meter fan dipoles in my attic in Atlanta to cover all directions.

The first issue is what space is accessible, as you have already mentioned. I rented a 2 bedroom villa in Chitty Chatty last summer. The attic had very limited accessible space for antenna. Consequently, I didn’t attempt to install anything in that attic. I used an AlexLoop instead. Your home may be different. Don’t hesitate to have some bends in your fan dipole legs if you can get the length you need that way. I have also thrown the end of a leg, with a weight on the end, to an area of an attic I couldn’t reach. It worked fine.

Of course, attic antennas are a compromise due to a few factors:
1. There are usually metal and other RF-unfriendly substances in the attic/roof to absorb or otherwise disturb your signal. They will also affect the resonant frequency.
2. The height above ground in The Villages will typically be 20’ or less giving higher than ideal takeoff angles, particularly on the lower bands.
3. There are often noise sources near an attic antenna, so you may have a high noise level.

On the positive side, it won’t cost you much to give it a try. Speaker wire from and TV coax from Loew’s will work for the fan dipole. You can use fishing line or string for insulation and connection to supports, especially with QRP.

If you find there is not accessible space in your attic for the fan dipole you envision, consider a couple of other options. The increasing sunspot count can provide a lot of contacts with modest antennas at low heights on 10-12-15 meters. You may be able to fit a fan dipole for those bands. You could also pick one band and install a 2 or 3 element wire yagi for it. Years ago, I put a 3 element 15 meter wire beam in my attic up 25 feet favoring Japan. It was 3 S-units better in that direction than my 40 meter dipole up 60 feet up broadside to Europe.

Let us know how it goes. I’m sure others can benefit from your experience.

73,
Jim AD4J

> On May 27, 2023, at 9:33 AM, Bob Easton <bob at bob-easton.com> wrote:
> 
> My primary interests, QRP HF CW, work fairly well from temporary verticals in my backyard. Those temporary antennas are great for short term use and portable operation. However, I'm looking for something more permanent and am considering a well tuned 4 band fan dipole inside the attic. (40m, 30m, 20m, 17m) Well tuned because I don't want to give up any of those 5 watts to a tuner, even though my favorite rig, a Penntec TR45-L, has a built-in Z-match tuner that can even out the rough edges.
> 
> I have lots of unknowns about such an antenna might fit and welcome the advice of others who have tried something similar. Among my unknowns are that I've never seen the inside of my attic, (don't yet have a ladder long enough - 10ft tall exterior walls and equally high ceilings). Nor do I know if the builder laid any sort of flooring up there. The house is about 3 years old, in Chitty-Chatty, south of US 44. Size wise, the overall dimensions of the building measure 72 feet on diagonals. So there should be enough space ... if I can get to it.  Assumption: wire antennas are inexpensive, while attic stairs and flooring not so much.
> 
> Will this be a good opportunity, or a multi-thousand dollar boondoggle? THANKS for all advice.
> 
> Bob, N4REE
> also: https://www.qrz.com/db/N4REE
> 
> -- 
> “Have nothing in your home that you do not know to be useful or believe to be beautiful.” - William Morris
> 
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